Carl Icahn

Net worth: $20 billion
At 77, Icahn enjoyed another strong run in 2012, beating the U.S. stock market and most hedge fund managers. The investment pool he manages for himself and his employees returned more than 20% in 2012, thanks to bets on Hain Celestial Group and CVR Energy. Icahn, who was born in Brooklyn and grew up in Queens, returned his hedge fund’s outside money in 2011. Separately, shares of his Icahn Enterprises, which invests in rail cars, retail, gaming, and energy, surged at the start of 2013. He started 2013 by locking horns with hedge fund trader Bill Ackman over Herbalife, the nutritional supplement seller Herbalife. Icahn took a roughly 13% position in the company after taking on Ackman in a verbal slugfest on CNBC. He returned the client money he managed in his hedge fund in 2011. The activist investor announced in 2012 that he is giving $200 million to the Mount Sinai School of Medicine and has given $40 million to support his six charter schools operating in the Bronx.